The present invention relates to driving axles, and particularly to tandem arrangements of driving axles having an input shaft driving a power divider which, in turn, drives one of the driving axles and also an output shaft for connection to the second driving axle. Typically, the power divider takes the form of an inter-axle differential having the carrier containing the differential or spider gears driven by the input shaft. In such an inter-axle differential arrangement, the differential gears typically drive, on one side thereof, a helical gear which meshes with a pinion shaft gear for driving the pinion of the first driving axle. The opposite side of the differential gears typically mesh with a gear formed on the output shaft for driving the second drive axle. Usually, a clutching arrangement is provided on the helical gear for locking the helical gear to the input shaft when loss of traction in encountered at the wheels. Locking the interaxle differential allows the torque to be transferred to the axle with the most available traction.
It is common practice in tandem driving axle arrangements to provide a thrust washer for absorbing the axial loading of the helical gear by the differential gears for driving the first driving axle. The thrust washer typically bears on one side thereof against the helical gear and on its other side against a shoulder provided on the input shaft with the helical gear disposed annularly about the input shaft for free rotation thereon when the clutch is disengaged.
In such a thrust washer arrangement, severe wear problems have been encountered in heavy service both at the thrust washer and the helical gear journal; and, it has been determined that the wear problems are due, in part, to insufficient lubrication. Typically, lubrication to the power divider component in a tandem drive axle arrangement has been provided by splash from the ring gear to which the pinion shaft is engaged in the first driving axle whereby lubricant is thrown from the ring gear into the power divider area. However, this method of splash lubrication from the ring gear has not provided sufficient lubrication to a thrust washer located on the opposite side of the differential gears from the ring gear.
Thus, it has long been desired to provide a simple, economical, and easily manufactured way or means of providing lubricant to the thrust washer in the power divider in a tandem drive axle.